Load transfer device



2 sheets-sheet 1 R. YEoMAN `1101.13 TRANSFER DEVICE y Filed .Aug. 15, 19:59

Nov. 4 194.14,

' INVENTOR .l/Meovwa RESISTANCE/5 y' RorAr/o/VAL ABOUT, THE Po//vr 0F ,QP/DU-y s/r/NTERsL-crs NEUTRAL PLA/vs CAr/o/vgfLoAo CAT/0N A R. c. YEOMAN LOAD TRANSFER DEVICE Filed Aug.` 15, 1939 Nov. 4, 1941.

APPL/cAT/o/vfyo I /VEUTRLPLANE R D., BVMW. o mNRm AOE V. l mrmR, m m ANT 1 f C wu w. F l 2 x @d f@ M d w, 262V E 5 mwa M T nrwmwMaLP AL .mopfonpy MMA .GSMOBMAPB Umm YENU www@ P mMArH.. hf TTL MVUAPO JAT load transmission unit which requiresl no great skill or expensive equipment to install. make, or use, and which may bepermanently sealed; a load transfer device for holding the ends of adjacent concrete road slabs in surface alignment while providing for the relatively lateral expan.

Y `crete road slabs-showingmy device in elevation;

Fig. 2 illustrates a section on line 2- 2 of Fig. 1;-

3 isja'sectional view online )#3 of Fig. 2; Fig. 4'is an elevationtaken-online of Fig.

YFigs. 5, 6 and "lare diagrammatical presentawith the end face of its companion slab as shown, and the anchors I2 extend back into the body of the slab, preferably both above and below the neutral plane of the slab.

From the face of the hub projects an integral;

"f chor or arm I2v is terminated in a foot or shoe It to provide `a substantial key to the concrete. Referring particularly to Fig. 3 of the drawings..

itwill be seen that the, cup-like sleeve-portionv generally designated 'I I, lextends back from its -face |,3, and the bore .I5 is enlarged backof this face which establishesa 'shoulder I'I invits top wall and a similar shoulder Itin its bottom wall.

tions ofthe elementaryfunctionsinherentto my invention. l Y i The structure illustrated involves the specific application of one form of my invention to a roadway slab. For purposes of description only, I chooseto so define my`invention as `applied to this particular constructi'onfr however," I wish -it understood that my invention isequally efl'ective when adapted or used in any poured. or precast structure,wihether it be a'roadway slab, retaining walL-swimming pool, reservoir, canal lining, warehouse fioor,dock, industrial plant, sidewalk, driveway, airport runway, bridge,; etc., for, as a lmatter of fact, ,it is applicable to 'an almost unlimited numberof structures.v And while I describemy invention in its preferred'embodiment, f

itis to lbe further understood Vthat the words which I use are words of descriptionand not of limitation. Reference characters refer-to similar parts throughout theseveral views oi' lthe drawings.

My invention contemplates a load transfer device for bridging a gap between the adjacent ends of two horizontally disposed and aligned concrete slabs 1 and I with opposed end faces l andA I, and comprises twocounterpart and relatively reversed rigid members 9 and I0 having their major Into this'sleeve istted av spring member I8 adapted to, conform in general with the contour of 'the bore, the Spring has its top portion 2li flanged outwardly to impinge and lock against the shoulder I1 and likewise hasits bottom portion 2i flanged .outwardlybut inaserrated pattern to impinge and lack against the shoulderIl ing a part of the spring in the air space between the end of the bridge and the rear wall of the `cup-like portion II, and another part of the spring alongside ofthe bridge (Fig. 3)

, Operation Inoperation, two identical units 9y and IIIare V'usually employed.A As a pair they are duplex in character; .design and function. n Each has two complemental parts-the bridge Il and the sleeve Il.' Each operatesat thesame time in the same way.' that is, the bridge 4I4 on one and the Y bearing seat on the other act or cofoperate siparts respectively imbedded in the two slabs, po-

sitioned at substantially mid-depth ofthe slabs,

. havingtheir major axis parallel vwith the ,top surface thereof, normal to the plane of the joint, and .spacedjin pairs at intervals throughout the width of the slab.

Each bridge or unit which preferably comprises vthe pair of malleable .castings Q-III islduplex in character; they are complemental toeach oth- .er-interchangeable The casting for the bridge member 9 may be made from the saine pattern y as is the casting for the bridge member I0. y Y

V,Each casting .or major part comprises a cuplike sleeve portion II openingat the end of the slab in which that partis imbedded and having face I3 of the sleeve Hpreferably is cast flush multaneously, thus differentiating from the common `dowel--tiie simpler form, and likewise differentiating from those structures employing'the `useof a dowel in assembly.

As shown at Fig. `1 a strip of asphalt, saturated feltv or joint member 21 is placed inthe gap between the end faces 5 and 6 of adjacent concrete road slabs 'I and 8 (I haveshown this particular type of joint member for illustration only, as any of the well known designs of joints such as the air cushion metallic joint, rubber joint or metal plate may be employed with equal effect). Openings are made in the joint member through which openings pass thebridges Il as a pairof units l and I0 are assembled one on each side of the joint member with ktheir respective faces I3 flush with andtightly locked against the outer Iwalls of the joint member. The bridge I4 of the funit 9 entering the sleeve II` of the unit I0 and the bridge Il of the unit III entering the-sleeveII in the unit y 9. nd the units'arecajst to the slabs inthis remembers is on the sides and bottom. There bel ing no clearance between' the top surface of the bridge'and the internal bearing surface of the sleeve, maximum bearing is constantlymaintained'as differentiating from the common dowel its bearing For illustration-as the moving wheelgloadwhich has to deflect to seat or ilnd however' so small the clearance be.

passes from theV slab 'Iltowards 'and onto the slab 8, slab ldeflects, the load is picked up by the unit land carried across the joint on the bridgev Il of the unit I0. When the load continues on and passes over the Joint to slab I, the unit III picks up the load which in turn is carried back bridging .strength as illustrated trates umfuth "greater section .modulus or ythe members opposes-the bending moment may be installed in plastic concrete, cast in situ;

and distributed into the slab 1 through the bridge I4 on the unit 9. There is here a reversal.

but not a reversal of stress in the bridging ele ment Il per se. The individual bridging element I l of each unit, due to its clearance on the bottom and its constant bearing on top carries the load in but one direction' only as compared to the common dowel assembly whereby the dowela single element-is constantly subjected to a reversal of stress which has been found to be fatigung and highly detrimental, calling for a greatly increased cross-section and double bearing surfaces.

In assemblyV and installation it is desirable that Athe units be aillxed to the joint member, the completed assembly then installed on the subgrade 24 as a unit. T o do this it is particularly advantageous that the load transfer units be locked or afllxed to the joint member in a manner preventing their accidental removal or displacement during this period. I have accomplished this feature by providing the spring I! in the sleeve portion of each unit. The bottom of the bridging element is adapted to frictionally engage the serrations as well as the flanged end 22 of the spring which exertsV pressure against the under side of the bridge and eilectively locks the units together regardless of any inequalities in the joint thickness. And as the assembled bridge does not extend the full depth of the bore provided in the sleeve of its complemental unit, an air chamber is established between the end wall of the sleeve and the end of the bridge which permits the slabs to uninterruptedly go and come due to their change in volume, with the consequent expanding and contracting of the joint space between the adjacent end faces of the respective slabs.

Referring particularly to Sheet 2 of the drawings, Figs. 5 6 and 7, it will be apparent to those skilled in the art that the anchors I2 are in reality radial anchors, radial about their neutral point under the point of application of load P o'n the bridge Il which is a point carried even beyond the face of the slab, to thus anchor and distribute the load back from the critical pointthe face of the slab. And as the fulcrum point approaches the face of the slab, the load P as it is'applied to the cantilever portion or bridge member I4, is distributed into the slab meeting with the rotational resistance of the anchors I2. This resistance is rotational about the point of application of load on the bridge member Il as it intersects the neutral planeof the installation which usually is mid-depth of the slab. Fig. 'l particularly illustrates the juxtaposed relationship of the assembled bridge members I4 of the units 9 and I0, andl graphically displays my statement that these bridging members are lateraly juxtaposed in a plane normal to the neutral plane of installation. Further, this ligure illusf each sleeve having a and whereas I have not shown the speciilc structure, I wish it understood that my invention is equally applicable to pre-cast concrete, art marble, imitation stone, glass,terra cotta kand other r products or combinations thereof.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is: v

1. A load transfer device for use in association f with adjoining concrete slabs, comprising a pair of spaced sleeves each having a horizontally disposed bore opening atv the face of its related slab,

horizontally disposed bridging member, the bridging members extending oppositely and adapted to span a'gap between the adjoining slabs, each bridging member extending into and slidably engaging the bottom face of the top wall oi' the bore of the oppositely disposed sleeve with a clearance between the bottom of each bridging member and the top face of the bottom `wall of the oppositely disposed sleeve, said clearance being of a dimension greatv, er than the deflection of the related slab when under normal load, so that a portion of the load applied to either sleeve is imparted in a downward direction only to the opposite sleeve, and means for anchoring each sleeve to its related slab.

2. A load transfer device as per claim 1, which includes independent means for yieldingly latching the bridging member to thebore of the oppositely disposed sleev said means being housed within thebore of the of the associated bridging' member.-

3. A load transfer wherein the means for its related slab comprises a pair of arms radially disposed about the neutral point under the point of application of load and symmetrical'with repect to a horizontal plane normal to the slab ace.

4. A load transfer device as per claim 1 wherein the bridging member variably decreases in height from its connection to the sleeve toits free extremity,

member is of uniform resistance at all points in its length to vertical bending underload.

5,. A load transfer tion with adjoining concrete slabs comprising a bearing member provided with anchoring means for anchoring the member to a slab, anda bridgmember has uniform, resistance to vertical bend-t ing at all points in its length.

6. A load transfer device for bridging a gapv between the adjacent ends of two substantially horizontally aligned concrete slabs comprising two complemental rigid members having their sleeve to engage a portion device as `per claim l,v anchoring eachvsleeve to the variation in height being such that the cantilever beam formed by the bridging device for use in associa- Vmajor parts respectively adapted to be imbetlded in their related slabs. eachmajor part comprising a cup-like sleeve portion opening at the end of the slab in which that part is imbedded and having the axis of its bore horizontal and at 5 right angles to said slab end, atongue-like bridging portion'horizontally offset'h'om itsfintegral vsleeve portion 'projecting beyond the mouth thereof and adapted to extend into and slidably engage the bore of the sieeveportion of the coml0 sleeve. portion and another part alongside` the tongue of its vcomplemental member.l

mit, cYnUs' 

